• Journal of the Korea Institute of Information and Communication Engineering
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• v.15 no.10
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• pp.2149-2156
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• 2011

In this paper, design of a new 3-dimensional (3-D) 16-ary signal constellation with constant envelope is presented and analyzed. Unlike the conventional 16-ary constellations, all signal points of the new constellation are uniformly located on the surface of a sphere so that they have a unique amplitude level and a symmetrical structure. When average power of the constellations is normalized, the presented 16-ary constellation has around 11.4% increased minimum Euclidean distance (MED) as compared to the conventional ones that have non-constant envelope. As a result, a digital communication system which exploits the presented constellation has 1.2dB improved symbol error rate (SER). While signal points of the conventional constant-envelope constellation are not distributed uniformly on the surface of a sphere, those of the proposed constellation has a completely symmetric distribution. In addition, the new signal constellation has much lower computational complexity for practical implementation than the conventional one. Hence, the proposed 3-D 16-ary signal constellation is appropriate for the application to a communication system which strongly requires a constant-envelope characteristic.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.445-450
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• 2000

In this paper, a numerical method is proposed for cam synthesis. kinematics of closed loop system with cam and follower is presented using relative coordinates. The system is transformed into an open loop system by cutting fictitiously higher-pair contact of cam and follower and envelope constraint equations are derived. Follower constraint equations are derived from the motion of the follower ends. The joint variables and follower profile parameters are calculated from the envelope constraint equations and follower constraint equations by using the Newton - Raphson iterative method. Algorithms for cam synthesis are presented and simulations are done to verify the effectiveness of the proposed method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2012.05a
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• pp.235-242
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• 2012

In recently constructed building, It has become fashionable again that the heavy external skin system such as a Stone Finished Envelope. There are Squared Steel Pipe Methods, C-Shaped Steel Pipe Methods, and Aluminum Beam Methods in the structure of a heavy external skin system. The Aluminum Beam Methods is often misunderstood as a Plane Truss Structure, but this method is not appropriate to be called to a truss structure but a beam methods. The Aluminum Beam Methods is the most Eco-friendly methods in terms of Quality assurance, Efficiency, Safety, Construction period, Durability, and Recyclability. And this Methods is also very appropriate in considering the point of Energy conservation, Waste reduction, Long-life architecture, Replacement parts, Environmental protection, Public efficiency, and Building demolition.

• Journal of Power Electronics
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• v.11 no.2
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• pp.228-236
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• 2011

The ${\Delta}\;V_{10}$ or 10-Hz flicker index, as a common method of measurement of voltage flicker severity in power systems, requires a high computational cost and a large amount of memory. In this paper, for measuring the ${\Delta}\;V_{10}$ index, a new method based on the Adaline (adaptive linear neuron) system, the FFT (fast Fourier transform), and the PSO (particle swarm optimization) algorithm is proposed. In this method, for reducing the sampling frequency, calculations are carried out on the envelope of a power system voltage that contains a flicker component. Extracting the envelope of the voltage is implemented by the Adaline system. In addition, in order to increase the accuracy in computing the flicker components, the PSO algorithm is used for reducing the spectral leakage error in the FFT calculations. Therefore, the proposed method has a lower computational cost in FFT computation due to the use of a smaller sampling window. It also requires less memory since it uses the envelope of the power system voltage. Moreover, it shows more accuracy because the PSO algorithm is used in the determination of the flicker frequency and the corresponding amplitude. The sensitivity of the proposed method with respect to the main frequency drift is very low. The proposed algorithm is evaluated by simulations. The validity of the simulations is proven by the implementation of the algorithm with an ARM microcontroller-based digital system. Finally, its function is evaluated with real-time measurements.

• Journal of the Korean Institute of Telematics and Electronics
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• v.10 no.1
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• pp.18-26
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• 1973

In AM detection system, when the ratio of the frequency of the carrier to that of the modulating signal becomes less than a ratio of approximately 10:1, AM detectors become unable to detect the impressed signal in a satisfactory waveform. The failure of detecting such a super wide-band AM signal resulting from charging and discharging transient phenomena in associated diode circuit during the detecting of AM signal, has been a cause of limiting the channel capacity in AM or FM super multiplexing systems. This Paper presents the "Poly-phase Envelope Detection System" as a suitable method to solve the problem and the analyses of the system suggested. This system will make it possible to take the envelope out of the impressed AM signal to any desired degree of accuracy even when the ratio of the frequency of the carrier to that of the modulating signal approaches unity. Experiments were carried out to verify the validity of the theory of Poly-phase Envelope Detection System by adopting the frequency conversion method from among the two proposals.proposals.

• Korean Journal of Construction Engineering and Management
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• v.14 no.4
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• pp.84-96
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• 2013

Recently, architectural design has been changing from formal design to freeform design due to the digitalization of construction industry. Especially, the formal design has been accepted as a design trend recently and applied many times as a design concept in the architectural design competitions such as turn-key. However, various deflects such as water leak and cracks have been occurred because the traditional construction methods had been applied without any revision or adaptation of the formal construction method for the freeform building construction. Design and construction of freeform building has been developed as an new method in order to solve the problems and minimize the construction duration and cost for the freeform building. Therefore this research deduced the positive implications for developing freefrom envelope by analyzing the domestic and abroad cases and proposed the considerations during design and construction of the freeform envelope as follows. First, the freeform design should consider the constructability for the freeform envelope. Second, manufacturing technology for the two-way curvature of the unit panel should be developed. Third, exposed concrete form method should be developed for the freeform envelope of concrete. Forth, material characteristics, construction method and facility management should be considered in order to manage precipitation and keep water-proof according to the classification of the freeform envelope area.

• Transactions of the Korean Society of Automotive Engineers
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• v.19 no.2
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• pp.72-77
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• 2011

In this paper, we propose effective diagnosis algorithm for hub bearing fault in driving vehicle using acceleration signal and wheel speed signal measured in hub bearing unit or knuckle. This algorithm consists of differential, envelope and power spectrum method. We developed diagnosis system for realizing proposed algorithm. This system consists of input device including acceleration sensor and wheel speed sensor, calculation device using Digital Signal Processor (DSP) and display device using Personal Digital Assistant (PDA). Using this diagnosis system, a driver can see hub bearing fault(flaking) from the vibration in driving vehicle. With early repairing, he can keep good ride feeling and prevent accident of vehicle resulting from hub bearing fault.

• Proceedings of the Optical Society of Korea Conference
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• 2006.02a
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• pp.141-142
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• 2006

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.1
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• pp.49-56
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• 2006

In this paper, to overcome the effect of nonlinear power amplifier, CE-CPSK(Constant Envelope Continuous Phase Shift Keying)modulation method which has the constant envelope and continuous phase characteristics is proposed. The code acquisition performances of the CE-CPSK modulated system and BPSK system are analyzed. And the performance is evaluated in terms of mean acquisition time and detection probability with the output backoff of the amplifier in multiuser environment. Results performed in a channel having a high degree of AM nonlinearity(AM-to-AM conversion), have shown that the CE-CPSK signal, when passed through class C-nonlinear Amplifier, has a spectrum with greatly reduced sidelobes compared to the conventional BPSK signal. The code acquisition performance of a CE-CPSK modulation system is better than that of BPSK system with nonlinear amplified multiuser environments.

• Korean Institute of Interior Design Journal
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• v.24 no.6
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• pp.221-228
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• 2015

This study aims to define concepts on Hospital Design Focused on System to respond to the development and change by comparing general design methods of the General hospital architecture in Korea and analyze elements suitable to concepts on Hospital Design Focused on System in the General hospital architecture through examining the transformation of General hospitals in Korea. Essential architectural elements composing the Hospital Design Focused on System are as follows. First of all, the elements which can react to development of hospital architecture are HOSPITAL STREET and site situation. Secondly, core, equipment shaft, column, MAIN STREET and air handling unit room are elements of great importance as the location of these elements determines the dimensions and scale of the space which hospital functions are assigned to. Third, the area in regard to the rate of change is formed by MAIN STREET, which is the primary element, and envelope. The depth between MAIN STREET and envelope is defined as space depth. The flexible area is determined depending on this space depth and thus how to set up this flexible area determines the degree of readiness in responding to the change.